Refuelable battery for the electric grid and method of using thereof

ABSTRACT

Systems and methods of the various embodiments may provide a refuelable battery for the power grid to provide a sustainable, cost-effective, and/or operationally efficient solution to energy source variability and/or energy demand variability. In particular, the systems and methods of the various embodiments may provide a refuelable primary battery solution that addresses bulk seasonal energy storage needs, variable demand needs, and other challenges.

RELATED APPLICATIONS

This application claims the benefit of priority to U.S. ProvisionalPatent Application 62/482,639 entitled “System and Method for aRefuelable Primary Battery for the Electric Grid” filed Apr. 6, 2017,the entire contents of which are hereby incorporated by reference forall purposes.

TECHNICAL FIELD

This invention relates generally to the field of grid battery power, andmore specifically to a new and useful system and method for a refuelablebattery power grid solution.

BACKGROUND

There is much interest in finding and implementing energy solutions thatmove towards renewable energy and having a lower environmental impact.In recent years, renewable energy sources such as solar and wind havegrown in usage. In many regions, initiatives are underway to movetowards fully renewable in the future. However, there are stillchallenges to achieving fully renewable power supply in all regions.

Variability in supply is one challenge. Supply can vary by geography,weather, climate, and other factors. Many forms of renewable electricityproduction rely on the seasons to provide stored energy. For example,snowpack in the mountains in winter provides water in the summer whichis used for hydropower. Additionally, renewable energy sources are oftentied to the availability of energy sources for a particular region.Wind, solar, hydro, and/or other sources have different levels ofapplicability and various seasonal factors depending on the region. Forexample, solar in regions higher in the northern hemisphere or lower inthe southern hemisphere will have seasonal trends. Technical solutionsfor seasonal variability currently don't exist.

Use of secondary batteries (i.e., batteries that are charged anddischarge through a reversible electrochemical reaction) as temporarystorage of power have received interest as a potential solution tovariability of renewable energy. An often-cited use case is that ofbatteries being able to store power from solar during the day, and thensupplying the grid with the power at night or times of low solar powersupply. However, this fails to address larger periods ofunpredictability. Secondary batteries are primarily designed to meet theneeds of frequent discharge and charge cycles as is typical in dailyusage cycles. Research has driven second batteries to be inexpensiveover many cycles, but too costly to use in low cycle applications.Furthermore, secondary batteries, despite considerable research, oftenrely on materials that are not sufficiently earth abundant.

SUMMARY

Systems and methods of the various embodiments may provide a refuelablebattery for the electric power grid and/or other power system to providea sustainable, cost-effective, and/or operationally efficient solutionto energy source variability and/or energy demand variability. Inparticular, the systems and methods of the various embodiments mayprovide a refuelable primary battery solution that addresses bulkseasonal energy storage needs, energy demand variation, and otherchallenges.

Systems and methods of the various embodiments may be employed incombination with a primary energy source connected to the power grid orother power requiring systems. The systems and methods of the variousembodiments may utilize primary battery units within a battery powersupply site. In various embodiments, the primary battery units may cyclethrough usage with a supply system supporting a “refueling process”on-site and/or offsite. In various embodiments, at the end of discharge,a primary battery unit may be decommissioned and the spent fuel (i.e.,battery chemical materials) removed and new fuel added. In variousembodiments, the refueling process may include the delivery, removal,and/or exchange of primary battery units and/or material components ofthe primary battery units. In various embodiments, the battery materialcomponents removed/exchanged in the primary battery units may includeanodes of the primary battery units and/or cathodes of the primarybattery units.

Various embodiments may provide a refuelable battery including a batterychamber configured to trap expended electrode material generated fromelectrode material of the battery while the battery is operating in adischarge mode. Expended electrode material may include oxidized anodematerial and/or reduced cathode material generated while the battery isoperating in a discharge mode. The expended electrode material may beremoved and reprocessed into recharged electrode material for use in thebattery according to various embodiments. Various embodiments mayprovide a refuelable battery including a battery chamber configured totrap anode material, such as oxidized anode particulate, oxidized anodepowder, oxidized anode shards, etc., generated from anode material ofthe battery while the battery is operating in a discharge mode. Theoxidized anode material may be removed and reprocessed into rechargedanode material for use in the battery according to various embodiments.Various embodiments may provide a refuelable battery including a batterychamber configured to trap cathode material, such as reduced cathodeparticulate, reduced cathode powder, reduced cathode shards, etc.,generated from cathode material of the battery while the battery isoperating in a discharge mode. The reduced cathode material may beremoved and reprocessed into recharged cathode material for use in thebattery according to various embodiments.

BRIEF DESCRIPTION OF THE FIGURES

The accompanying drawings, which are incorporated herein and constitutepart of this specification, illustrate example embodiments of theclaims, and together with the general description given above and thedetailed description given below, serve to explain the features of theclaims.

FIG. 1 is a schematic representation of an embodiment system;

FIG. 2 is a graph of an exemplary impact of embodiment systems andmethods on energy production by a solar farm;

FIG. 3 is a graph of an exemplary impact of embodiment systems andmethods on energy production by a wind farm;

FIG. 4 is a process flow diagram illustrating an embodiment method forrefueling and reprocessing primary battery units;

FIG. 5 is a process flow diagram illustrating another embodiment methodfor refueling primary battery units;

FIG. 6 is a block diagram illustrating the operation of components of anembodiment refuelable battery power grid system according to theembodiment method illustrated in FIG. 5;

FIG. 7 is a block diagram of an embodiment refuelable battery; and

FIG. 8 is a block diagram of another embodiment refuelable battery.

DETAILED DESCRIPTION

The various embodiments will be described in detail with reference tothe accompanying drawings. Wherever possible, the same reference numberswill be used throughout the drawings to refer to the same or like parts.References made to particular examples and implementations are forillustrative purposes and are not intended to limit the scope of theclaims. The following description of the embodiments of the invention isnot intended to limit the invention to these embodiments but rather toenable a person skilled in the art to make and use this invention.

Systems and methods of the various embodiments may provide a refuelablebattery to provide a sustainable, cost-effective, and/or operationallyefficient solution to matching energy supply and demand variability. Inparticular, the systems and methods of the various embodiments mayprovide a refuelable primary battery solution that addresses variouschallenges, including bulk seasonal energy storage needs, demandincrease response needs, etc.

Systems and methods of the various embodiments may be employed incombination with a primary energy source connected to a power grid. Thesystems and methods of the various embodiments may utilize primarybattery units within a battery power supply site. A primary battery unitor primary battery may be a battery unit or battery that is notrecharged through an electrochemical reaction. A battery power supplysite may be a site, such as a battery power plant or system, includingat least one battery configured to output energy, such as to a powergrid or other system. In various embodiments, the primary battery unitsmay cycle through usage with a supply system supporting a “refuelingprocess” which may be located on-site and/or offsite. In variousembodiments, at the end of discharge, a primary battery unit may bedecommissioned and the spent fuel (i.e., battery chemical materials,such as anode materials, cathode materials, etc.) removed and new fueladded. In various embodiments, the refueling process may include thedelivery, removal, and/or exchange of primary battery units and/ormaterial components of the primary battery units. In variousembodiments, the refueling process may include physical replacement ofelectrode materials (e.g., anode materials, cathode materials, etc.)within the primary battery units. For example, a primary battery unitmay be refueled by inserting a new anode and/or a new cathode into theprimary battery unit.

FIG. 1 illustrates a refuelable battery power grid system 100 accordingto various embodiments. In the refuelable battery power grid system 100,a refuelable battery power plant (or system) 101 may be set up on-siteat a renewable energy source 103 (e.g., a wind farm, hydroelectric dam,solar farm, etc.). The refuelable battery power grid system 100 mayinclude a battery power plant 101 that includes a plurality of connectedbattery units 110, such as primary battery units. The battery powerplant 101 may additionally include various systems configured to managethe operation and refueling of the battery power plant 101, such as anelectrical system 120, thermal management system 121, and control system122. The thermal management system 121 may include temperature sensingand regulating components. The electrical system 120 may include variouscomponents such as an inverter. In one variation, the inverter may be aunilateral power inverter. The control system 122 may manage operationof the set of primary battery units 110. The control system 122 mayadditionally include a data interface to a primary power system or anassociated data source. The control system 122 may facilitate selectionof primary battery units 110, activation of primary battery units 110,and/or other operations. In one mode of operation, the control system122 may utilize the primary battery units 110 in a manner at leastpartially coordinated with refueling capacity.

The refuelable battery power grid system 100 may function as an on-siteinstallation that interfaces with a consumer of the energy. The consumerof the energy may preferably be a connected power grid 102, but mayalternatively be any suitable system such as building, factory, or othersuitable energy powered system. The battery power plant 101 may beinstalled onsite with a renewable energy source 103, such as a windfarm, a hydroelectric plant, a solar farm, or any suitable energyproduction site. The renewable energy source 103 may connect to the grid102 directly via a primary power connection 105. The battery power plant101 may connect to the grid 102 via a supplementary power connection 104that connects to the grid 102 through the renewable energy source 103.In this manner, power supplied to the grid 102 from the battery powerplant 101 via the supplementary power connection 104 may appear to thegrid 102 as if received from the renewable energy source 103.

The battery power plant 101 may be setup with stationary equipment tosupport the operation of the refuelable battery power grid system 100.Transportation access may be positioned near the battery power plant 101to facilitate convenient refueling. Refueling of primary battery units110 may be handled using typically available machinery and tools. Afull-scale solution may then reprocess the battery materials of theprimary battery units 110 at a second site, such as reprocessing site104. In some cases, this reprocessing site 104 may be located in alocation with an alternative power source (such as an alternative powersource using renewable energy generated by renewable energy source 103(or another renewable energy source) during periods when renewableenergy is abundant). In other cases, the reprocessing site 104 may be inconnection with the power grid 102. In various embodiments, reprocessingof the primary battery units 110 may occur during seasonal periods thatresult in excess renewable energy generated by renewable energy source103 (or another renewable energy source).

In one variation, the battery power plant 101 may include dockingstations for the primary battery units 110. There will preferably be alarge number of primary battery units 110 that will be installed tosupplement power production over long seasonal periods. The number ofdocking stations may include enough docking stations to house activeprimary battery units 110, depleted primary battery units 110 awaitingrefueling/removal, and reserve primary battery units 110. When a primarybattery unit 110 is depleted it will need to be refueled, and as such,there are preferably sufficient docking stations so that the powersupply target may be satisfied while primary battery units 110 are beingrefueled before the active primary battery units 110 are depleted.

The battery power plant 101 may include an array of docking stations. Inone variation, the docking stations may allow stacking of primarybattery units 110. In some variations, the battery power plant 101 mayinclude lifts and/or conveyors to facilitate installing/instantiatingand/or removal of primary battery power units.

The primary battery unit 110 functions as the source of power. Theprimary battery unit 110 includes primary battery elements that may useany suitable chemistry such as Al, AlCl₃, Fe, FeO_(x)(OH)_(y),Na_(x)S_(y), SiO_(x)(OH)_(y), AlO_(x)(OH)_(y), and/or any suitable typeof primary battery chemistry. Similarly, the primary battery unit 110may use a solid material, such as a sheet, foil, rod, or disc for theprimary battery active material. In certain other embodiments, theprimary battery unit 110 may use a powdery form, such as a particulate,for the primary battery active material. In certain other embodiments,the primary battery unit 110 may use a slurry such as a colloid,suspension, or dispersion suitable material state for the primarybattery active material.

The primary battery units 110 may additionally include an activatormechanism wherein, the materials of the primary battery unit 110 can bekept separated or otherwise inactive until it nears the time for use ofthe primary battery unit 110. This may function to better hold energyduring storage by mitigating self-discharge reactions which occur whenthe primary battery active material is in contact with the electrolyte.

The primary battery unit 110 may be composed of multiple cells.Individual battery cells maybe any suitable form factor. Additionally, aprimary battery unit 110 itself may be composed of sub-units. Forexample, a primary battery unit 110 may be a container that can containa number of sub-units, which may be exchangeable by human workers ormachines. In part because of the amount of energy the refuelable batterypower grid system 100 is expected to deliver, the primary battery units110 may have a large form factor (e.g., several hundred or thousandpounds).

The primary battery units 110 may use materials that are earth abundant,non-toxic, recyclable/reusable, and cost effective. In variousembodiments, the primary battery units 110 may be processed and/orreprocessed at scale at dedicated sites, such as reprocessing site 104.Primary battery units 110 and/or the refueling material used in theprimary battery units 110 may be transported onsite for use withrefuelable battery power grid system 100.

In some refueling options, the primary battery units 110 may beexchanged as a form of refueling the energy supply. In someimplementations, the primary battery unit 110 may include a housing thatconforms to a form factor compatible with shipping containers, which maymake the primary battery unit 110 easily transported using standardindustrial equipment such as forklifts, cranes, conveyors, and alsoloaded onto trucks or onto trains.

In an alternative refueling option, the primary battery units 110 mayhave depleted material removed and processed material added. Depleted(i.e., expended) electrode materials may be removed and processed (i.e.,new or recharged) electrode material may be added. For example, an anodematerial of the primary battery unit 110 may oxidize during dischargeinto oxidized anode material, such as oxidized anode particulate,oxidized anode powder, oxidized anode shards, etc., that may be removed,reprocessed at the reprocessing site 104 into a new anode material, andthe new reprocessed anode material may be inserted into the primarybattery unit 110 to thereby refuel the primary battery unit 110. Asanother example, a cathode material of the primary battery unit 110 mayreduce during discharge into reduced cathode material, such as reducedcathode particulate, reduced cathode powder, reduced cathode shards,etc., that may be removed, reprocessed at the reprocessing site 104 intoa new cathode material, and the new reprocessed cathode material may beinserted into the primary battery unit 110 to thereby refuel the primarybattery unit 110. The primary battery unit 110 may include a materialrefueling supply system that may manage or facilitate removal anddeposit of materials to renew the stored energy of the primary batteryunits. For example, the primary battery unit 110 may include pumpsand/or circulation systems to facilitate removal and deposit ofmaterials. Additionally, the primary battery unit 110 may include accessports to enable material to be placed into the primary battery unit 110,such as refueled electrode material (e.g., refueled anode and/or cathodematerial) to be placed on one or more electrode supports (e.g., one ormore anode and/or cathode supports) in the primary battery unit 110. Theprimary battery unit 110 may include access ports to enable material tobe removed from the primary battery unit 110, such as expended electrodematerial (e.g., oxidized anode material such as oxidized anodeparticulate, oxidized anode powder, oxidized anode shards, etc. and/orreduced cathode material such as reduced cathode particulate, reducedcathode powder, reduced cathode shards etc.) generated while the primarybattery unit 110 is operating in a discharge mode. Further, the primarybattery unit 110 may include valves and other partitions operable tofluidically isolate portions of the primary battery unit 110 from oneanother to support insertion or removal of material from the primarybattery unit 110. For example, a filter area trapping oxidized anodematerial may be fluidically isolated from the rest of the primarybattery unit 110 to enable the electrolyte to be drained from the filterarea and the oxidized anode material to be removed to be reprocessedinto new anode material at the reprocessing site 104. Similarly, afilter area may trap reduced cathode material and may be fluidicallyisolated from the rest of the primary battery unit 110 to enable theelectrolyte to be drained from the filter area and the reduced cathodematerial to be removed to be reprocessed into new cathode material atthe reprocessing site 104. As another example, valves and pumps mayenable the electrolyte level of the primary battery unit 110 to beraised and/or lowered.

The primary battery unit 110 may include integrated unit controlsystems, power management, thermal systems, data connections, and/orother features. The primary battery unit 110 may additionally include apower and control interface such that it can be installed and removedfrom a docking station. The power and control interface may beconfigured to automatically connect when inserted into the dockingstation. Alternatively, the primary battery unit 110 may be manuallyconnected to the battery power plant 101.

In some variations, the refuelable battery power grid system 100 mayinclude a mixture of battery power sources, which can include batterieswith different chemistries. In some variations, secondary batteries maybe integrated into the refuelable battery power grid system 100 toprovide temporary storage of excess storage alongside bulk energystorage of the primary battery units 110. For example, the refuelablebattery power grid system 100 may include electrochemically rechargeablelithium-ion batteries along with the primary battery units 110.

The reprocessing site 104 may be a refueling system that functions tofacilitate the restocking of energized primary battery units 110 afterthey are depleted. For example, the reprocessing site 104 mayrestock/reenergize the electrode materials after they areexpended/depleted. As a specific example, when the primary battery unitsutilize iron based anodes that need restocking/reenergizing, oxidizedanode material from the primary battery units 110 may be reprocessedinto new anode material by reduction (e.g., direct reduction iron (DRI)processing, hot briquetted iron (HBI) processing, etc.), smelting,electrolysis, or any other reprocessing operation (e.g., anymetallurgical process that generates new anode material) at thereprocessing site 104.

In a first variation, the primary battery units 110 may be reprocessed.Such reprocessing may include the removal of the primary battery unit110 from the battery power plant 101, transport to the reprocessing site104, where reusable components and materials may be extracted andreprocessed into an energized primary battery unit 110. In some cases,non-reusable materials and components may be recycled, disposed of,and/or replaced. In an implementation, reprocessing may be performed ata site with a source of renewable energy. Reprocessing may alternativelyhappen at the same site as the battery power plant 101 and in some casesmay be performed during the season when there is excess renewable energygenerated by renewable energy source 103.

In another variation, the primary battery units 110 have a chemicalmakeup where material may be extracted and replaced to energize theprimary battery unit 110. For example, expended electrode material maybe collected and removed for reprocessing. As a specific example, asanode material of a primary battery unit 110 is oxidized it may becollected and removed for reprocessing. The reprocessing at thereprocessing site 104 may generate new anode material that may then beinserted into the primary battery unit 110 to refuel the primary batteryunit 110. Thus, the entire primary battery unit 110 may not be removedfor reprocessing, and only a portion of the materials within the primarybattery unit 110 may be removed for reprocessing. The refuelable batterypower grid system 100 and battery power plant 101 may incorporatemechanisms to support the efficient material removal and materialdepositing in depleted primary battery units 110. For example, theprimary battery unit 110 may include pumps and/or circulation systems tofacilitate removal and deposit of materials. Additionally, the primarybattery unit 110 may include access ports to enable material to beplaced into the primary battery unit 110, such as refueled anode and/orcathode material to be placed on one or more anode and/or cathodesupports in the primary battery unit 110. The primary battery unit 110may include access ports to enable material to be removed from theprimary battery unit 110, such as expended electrode material (e.g.,oxidized anode material such as oxidized anode particulate, oxidizedanode powder, oxidized anode shards, etc. and/or reduced cathodematerial such as reduced cathode particulate, reduced cathode powder,reduced cathode shards etc.) generated while the primary battery unit110 is operating in a discharge mode. Further, the primary battery unit110 may include valves and other partitions operable to fluidicallyisolate portions of the primary battery unit 110 from one another tosupport insertion or removal of material from the primary battery unit110. For example, a filter area trapping oxidized anode material may befluidically isolated from the rest of the primary battery unit 110 toenable the electrolyte to be drained from the filter area and theoxidized anode material to be removed to be reprocessed into new anodematerial at the reprocessing site 104. Similarly, a filter area may trapreduced cathode material and may be fluidically isolated from the restof the primary battery unit 110 to enable the electrolyte to be drainedfrom the filter area and the reduced cathode material to be removed tobe reprocessed into new cathode material at the reprocessing site 104.As another example, valves and pumps may enable the electrolyte level ofthe primary battery unit 110 to be raised and/or lowered.

As one potential benefit, the refuelable battery power grid system 100may offer energy at scale during periods of seasonally low renewablepower availability. The battery power plant 101 may be customized toaccount for long seasonal patterns in use. Related to the use as aseasonal power supply, the battery power plant 101 may offer long-termbattery energy storage that enables power management responsive toseasonal usage patterns. The battery power plant 101 may additionally oralternatively be used with non-seasonal variables.

As another potential benefit, the battery power plant 101 may mitigatereliance on conventional sources of electricity generation. Seasonaldeclines in renewable energy supplies generated by the renewable energysource 103 may be offset by the battery power plant 101. The batterypower plant 101 may be used for a sustained period during low or norenewable energy supply. For example, solar power from the renewableenergy source 103 may be used primarily during the summer to providepower to the grid 102, and the battery power plant 101 may be primarilyused during winter months to provide power to the grid 102.

As a related potential benefit, the battery power plant 101 mayeffectively increase the renewable energy production ratings of therenewable power source 103. Without a bulk energy storage solution, arenewable power source 103 may be granted a power rating based onexpected power and coverage capabilities. Seasonal declines and/orunpredictability of the renewable power source 103 conventionally resultin lower ratings meaning renewable energy sources are relied upon less.However, the battery power plant 101 may normalize the power ratings ofthe renewable energy source 103 such that the renewable energy source103 may operate with power ratings closer to peak power capabilities.

As another potential benefit, the battery power plant 101 may use amodular design, which may function to enable the battery power plant 101to scale for different use-cases.

As yet another potential benefit, the battery power plant 101 mayfunction to transform renewable energy into a material good in the formof primary battery units 110 that may be shipped and transported.

Herein, the various embodiments are primarily discussed as they may beapplied in combination with renewable energy. In solar energyproduction, the battery power plants of the various embodiments, such asbattery power plant 101, may be used in supplementing solar energyproduction during the winter months. FIG. 2 is a graph of power outputover time of an embodiment system including a battery power plant, suchas battery power plant 101, connected to a renewable energy source, suchas renewable energy source 103, wherein the renewable energy source is asolar farm. As shown in FIG. 2, the actual solar farm power productionindicated by the dashed line may vary seasonally over the course of ayear, but the supplemental power provided by the battery power plantduring the lower solar power production times may enable the total poweroutput of the embodiment system to remain constant over the course ofthe year as indicated by the solid line. Hydroelectric power systemsthat rely on the melting of snowcaps may have similar seasonal patternsto solar systems, and the battery power plants may similarly supplementhydroelectric power systems to offset season patterns.

In wind energy production, the various embodiment battery power plants,such as battery power plant 101, may be used on demand to account forseasonal and short-term variability in wind energy production. FIG. 3 isa graph of power output over time of an embodiment system including abattery power plant, such as battery power plant 101, connected to arenewable energy source, such as renewable energy source 103, whereinthe renewable energy source is a wind farm. As shown in FIG. 3, theactual wind farm power production indicated by the dashed line may varyseasonally and due to short-term wind changes over the course of a year,but the supplemental power provided by the battery power plant duringthe lower wind power production times may enable the total power outputof the embodiment system to remain constant over the course of the yearas indicated by the solid line.

The various embodiments may also be applied to other type renewableand/or conventional power sources. For example, the battery power plantsof the various embodiments, such as battery power plant 101, mayfacilitate transitions between energy sources as a region decommissionsa power plant and/or onboards a new power plant. The battery powerplants of the various embodiments, such as battery power plant 101, maysimilarly be used off-grid as a secondary power option for a site oreven as the primary power option.

FIG. 4 is a process flow diagram illustrating an embodiment method 400for operating a refuelable battery power system and specifically forrefueling and reprocessing primary batteries. The operations of method400 may be performed using one or more components of the embodimentrefuelable battery power systems described herein, such as refuelablebattery power grid system 100. The method 400 may include instantiatinga set of refuelable battery units at a site in step 402, monitoring astate of at least one power system, such as at least one grid system,and cycling use of primary battery units in step 404, refueling theprimary battery units in step 406, and reprocessing the primary batteryunits in step 407.

Step 402, which may include instantiating a set of refuelable batteryunits at a site, functions to setup a number of primary battery powersources for long-term storage to supply energy at a site. Instantiatingthe refuelable battery units may include delivering the set ofrefuelable battery units and installing them in a battery power plantthat interfaces with a grid or other power consuming/delivery system.

Step 404, which includes monitoring a state of at least one powersystem, such as at least one grid system, and cycling use of primarybattery units, functions to manage the set of primary battery units soas to supplement another power supply. The primary battery units may bereserved to supplement a renewable power source over a long durationsuch as over one or more weeks, one or more months, a year, or multipleyears. The primary battery units may be activated and used untildepleted. When they are depleted or nearing end of their useful life,the primary battery units may be identified as needing “refueling”.During the next refueling process the primary battery units in need ofrefueling may be removed or otherwise refueled.

Step 406, which includes refueling the primary batteries, functions toreprocess and/or replace the primary batteries used in the primarybattery units. In a first variation, the battery components of primarybattery units can be reprocessed in step 407. Material reprocessing caninvolve transport to a reprocessing site, reprocessing, transportingback to the site of the battery power plant, and reinstalling into thebattery power plant in step 402. In some variations, the offsitelocation is in a region that has more access to renewable energy duringthe refueling periods. In this way renewable energy can be applied inthe manufacturing processing of the battery fuel.

In another variation, the battery components of the primary batteryunits can be exchanged with new materials. Thus, the primary batteryunits themselves may only be installed once, but the materials withinthe primary battery units may be removed, reprocessed, and replaced torefuel the primary battery units. The primary battery units can be keptin place with battery materials exchanged. Such reprocessing operationsmay be particularly feasible with the seasonal patterns of renewableenergy. For example, a battery power plant, such as battery power plant101, may be used primarily in winter months and then refueled duringover the summer months in time for winter.

FIG. 5 is a process flow diagram illustrating an embodiment method 500for refueling materials within primary battery units, such as primaryunits 110 of refuelable battery power grid system 100. The operations ofmethod 500 may be performed using one or more components of theembodiment refuelable battery power grid systems described herein, suchas refuelable battery power grid system 100. In various embodiments, theoperations of method 500 may be performed in conjunction with one ormore of the operations of method 400 (FIG. 4).

In step 502, the battery power plant, such as battery power plant 101,may be operated to discharge power. To discharge power one or moreprimary battery units, such as one or more primary battery units 110, ofthe battery power plant, such as battery power plant 101, may beoperated in a discharge mode. For example, the primary battery units 110may be operated in a discharge mode to generate and provide supplementalpower to the grid 102 to offset drops in power generation by renewableenergy source 103. The primary battery units 110 may be operated in thedischarge mode to generate and provide supplemental power to the grid102 and renewable energy source 103 over a long duration such as overone or more weeks, one or more months, a year, and/or multiple years.The discharge of power from the battery power plant, such as batterypower plant 101 may occur for a timeframe that is seasonal, such as fora timeframe of one or more weeks, months, seasons, and/or years. Suchseasonal timeframe discharges from the battery power plant, such asbattery power plant 101, may be longer in duration than hourly or dailydischarges and may offset seasonal reductions in the ability ofrenewable energy sources, such as renewable energy source 103, togenerate power.

In step 504, the spent fuel from the primary battery units, such asprimary battery units 110, may be collected and removed. In variousembodiments, as the primary battery units 110 are operated in adischarge mode to generate power, anode material (i.e., charged fuel) ofthe primary battery unit 110 may oxidize and the oxidized anode material(i.e., the spent fuel) may be collected and removed for reprocessing. Ina similar manner, in various embodiments, as the primary battery units110 are operated in a discharge mode to generate power, cathode material(i.e., charged fuel) of the primary battery unit 110 may be reduced andthe reduced cathode material (i.e., the spent fuel) may be collected andremoved for reprocessing. In some embodiments, the charged fuel mayoxidize in place and the fuel material may be removed directly from itssupport within the primary battery unit 110. For example, in anelectrolyte solution with a pH greater than 6, an iron anode may oxidizein place to form an oxidized anode material, such as oxidized anodeparticulate, oxidized anode powder, oxidized anode shards, etc., ofFe(OH)₂, Fe(OH)₃, Fe₂O₃, Fe₃O₄, FeOOH, or combinations thereof. In someembodiments, the charged fuel may oxidize and circulate into theelectrolyte where it may be filtered out for removal. For example, in ahigh pH electrolyte solution (e.g., with a pH greater than 6) an ironanode may form an oxidized anode material, such as oxidized anodeparticulate, oxidized anode powder, oxidized anode shards, etc., ofFe(OH)₂, Fe(OH)₃,Fe₂O₃, Fe₃O₄, FeOOH, or combinations thereof in theelectrolyte and the electrolyte may be filtered (such as in a filterarea) to trap and remove the oxidized anode material. In someembodiments, the filter area may include a foam, such as a seeded foam,to trap the oxidized anode material as the electrolyte circulatesthrough the filter area. The foam may be seeded with a metal hydroxide(OH), such as calcium hydroxide (CaOH). In some embodiments, the filterarea may be a bag or other type container, removable from the primarybattery unit 110 in which oxidized anode material, such as oxidizedanode particulate, oxidized anode powder, oxidized anode shards, etc.,may be collected. In various embodiments in which cathode material is tobe removed, a filter area may trap and remove reduced cathode materialin similar manners as discussed above. In various embodiments,electrolyte levels in the primary battery units 110 may be raised and/orlowered to facilitate collection and removal of spent fuel. As examples,pumps, valves, and other partitions of the primary battery units 110 maybe used to fluidically isolate portions of the primary battery units 110to enable the electrolyte levels in the primary battery units 110 to beraised and/or lowered to facilitate collection and removal of spentfuel.

In step 506, the spent fuel may be reprocessed into charged fuel. Forexample, the spent fuel may be reprocessed into charged fuel at thereprocessing site 104. In embodiments in which the primary battery units110 may utilize iron based anodes that need restocking/reenergizing,oxidized anode material (i.e., spent fuel) from the primary batteryunits 110 may be reprocessed into new anode material (i.e., chargedfuel) by reduction (e.g., DRI processing, HBI processing, etc.),smelting, electrolysis, or any other reprocessing operation (e.g., anymetallurgical process that restocks/reenergizes anode material). In someembodiments, additives may be added to the spent fuel duringreprocessing. For example, carbon (e.g., graphite) may be added to thespent fuel during reprocessing. This additional carbon may help withreduction of the spent fuel into charged fuel. Alternatively, carbon(e.g., graphite) may be added to the anode during the anodemanufacturing. This additional carbon may increase conductivity of theanode during the battery operation and help with reduction of the spentfuel (i.e., oxidized anode material) into charged fuel during thereduction process via a carbothermal reduction process at thereprocessing site 104. In some embodiments, the reprocessing may includecarbon based thermal reduction using natural gas or coal burningfurnaces which may add carbon to the charged fuel. In some embodiments,the spent fuel reprocessing of step 506 may include reprocessing spentcathode material into recharged cathode material.

In some embodiments, the energy used for reprocessing the spent fuelinto charged fuel may come from renewable energy sources, such asrenewable energy source 103 or another renewable energy source. Forexample, when reprocessing site 104 and renewable energy source 103 areco-located, the renewable energy source 103 may provide the power forthe reprocessing operations of reprocessing site 104, such as when therenewable energy source 103 has excess power available (e.g., duringsummer months for solar farms, high wind periods for wind farms, springthaws for hydroelectric dams, etc.). In this manner, during seasonalperiods of high renewable energy output, a portion of the excessrenewable energy may be used for fuel reprocessing.

In step 508, the charged fuel may be inserted into the battery powerplant. For example, new anode material formed from reprocessing thespent fuel into charged fuel in step 506 may be placed onto anodesupports of the primary battery units 110 in step 508 to thereby refuelthe primary battery units 110. As another example, new cathode materialformed from reprocessing the spent fuel into charged fuel in step 506may be placed onto cathode supports of the primary battery units 110 instep 508 to thereby refuel the primary battery units 110. The chargedfuel (e.g., a Fe anode, etc.) may be placed into a battery chamber ofthe primary battery unit through an opening in the battery chamber(e.g., an access port) and onto a support, such as an anode support,cathode support, etc. With the new charged anode and/or cathode theprimary battery unit 110 may be refueled and the method may proceed tostep 502 to operate the primary battery unit 110 in discharge mode asneeded.

In various embodiments, the primary battery units, such as primarybattery units 110, may be air-breathing batteries and the refueling ofthe primary battery units in step 504 may include collection and removalof anode material and the charged fuel inserted in step 508 may be newanode material. In various embodiments, the refueling of the primarybattery units in step 504 may include collection and removal of cathodematerial and the charged fuel inserted in step 508 may be new cathodematerial. In some embodiments, the primary battery units, such asprimary battery units 110, may be non-air-breathing batteries having twodifferent materials used as electrodes, such as one metal oxide, such asan ore or mineral, for the cathode and one metal for the anode. One ofthe electrodes may be recharge/renewed after discharge and the otherelectrode may be removed and sold or otherwise consumed as anelectrorefined metal. That removed and sold or otherwise consumedelectrode may be partially or entirely replaced with a new electrode.For example, one metal may be in the oxidized state and the other metalin the reduced state (e.g., Fe₂O₃ and Al). The primary battery unit maybe operated in a discharge mode and one of the two metals of the cathodeand/or anode may be processed into an electrorefined metal duringdischarge that may have value. For example, the couple including Fe₂O₃and Al would produce iron (Fe) metal and aluminum oxide (Al₂O₃). Theelectrorefined metal may be removed from the primary battery unit andsold or otherwise consumed. That electrode that resulted in theelectrorefined metal (e.g., the original cathode or original anode) maybe replaced with an entirely new electrode. The other metal may reduceor oxidize into an expended electrode material (e.g., reduced cathodematerial or oxidized anode material). The expended electrode material(e.g., reduced cathode material or oxidized anode material) may beprocessed into a recharge electrode material (e.g., recharge cathodematerial or recharge anode material) and replaced back into the batteryto refuel the primary battery unit. In this manner, while bothelectrodes may be replaced, only one of the two electrodes may beprocessed into new fuel for the primary battery unit.

FIG. 6 is a block diagram illustrating the operation of components of anembodiment refuelable battery power grid system, such as refuelablebattery power grid system 100, operated according to the embodimentmethod 500 illustrated in FIG. 5. FIG. 6 illustrates a single batteryunit 110, such as primary or secondary battery unit. For example, theprimary battery unit 110 may be an iron-air (Fe-air) battery that ismechanically refuelable. Alternatively, the primary battery unit 110 maybe a battery with an anode including iron (Fe), zinc (Zn), magnesium(Mg), aluminum (Al), or an alloy formed substantially of one or more ofiron, zinc, magnesium and/or aluminum. The primary battery unit 110 maybe a battery with an anode including iron (Fe) or an iron alloy. Theprimary battery unit 110 may be a battery with an anode including zinc(Zn) or a zinc alloy. The primary battery unit 110 may be a battery withan anode including magnesium (Mg) or a magnesium alloy. The primarybattery unit 110 may be a battery with an anode including aluminum (Al)or an aluminum alloy. The primary battery unit 110 may be anon-air-breathing battery. The primary battery unit 110 may include abattery chamber 600 supporting the anode 602 and at least one cathode603 in an electrolyte 601. The anode 602 may be an anode materialdisposed on an anode support, such as a bed, mesh, foil, or otherscaffold, within the battery chamber 600. The anode 602 may includeiron(Fe), zinc (Zn), magnesium (Mg), aluminum (Al), and/or an alloyformed substantially of one or more of iron, zinc, magnesium and/oraluminum. In certain embodiments, the anode 602 may be a monolithicanode, including only a single phase of matter. For example, the anode602 may be a block, plate, sheet, or foil of metal and the anode 602 maybe dense or porous. In certain embodiments it may be advantageous forthe anode 602 to be porous to allow liquid electrolyte to infiltrate theanode 602 to increase the surface area of contact between the metalanode 602 and liquid electrolyte 601 and to promote rapid ion transportthrough the anode 602. In certain other embodiments, it may beadvantageous to have a dense metal electrode to minimize the volume ofthe anode 602. In certain other embodiments, the anode 602 may becomprised of multiple phases of matter, such as a metal powder and aninert (i.e. non-reactive) material such as carbon or a polymeric binder.The addition of an inert material may improve the electrochemical and/ormechanical properties of the anode 602. For example, the anode materialin the anode 602 may be powdered Fe and a binder material, wherein thebinder is added to improve the mechanical integrity of the electrode. Incertain other embodiments, the anode material in the anode 602 may bepowdered Fe and a carbon material, wherein the carbon is added toimprove the electrical conductivity of the electrode. In certain otherembodiments, the anode material in the anode 602 may be powdered Fe, abinder material, and carbon, where the anode 602 enjoys the benefits ofboth improved mechanical integrity from the binder and improvedelectrical conductivity from the carbon.

The cathode 603 may be a gas diffusion electrode to enable reactionswhich have a combination of liquid and gaseous reactants and products.The cathode 603 may be formed from a porous support material(alternatively called a scaffold or substrate) which may be optionallydecorated with a catalyst to improve the interfacial reaction kinetics.The cathode 603 may be formed from various materials, such as carbon(C), nickel (Ni), or titanium (Ti), or nickel-iron alloys (NiFe). Thecathode 603 may be optionally decorated with a catalyst known to promotethe desired discharge reaction.

The primary battery unit 110 may receive air into the battery chamber600 via one or more air inlets in the battery chamber 600. The airinlets may act as oxygen inlets providing air including oxygen (O₂) intothe battery chamber 600. In some embodiments, the primary battery unit110 may receive oxygen (0 ₂) into the battery chamber 600 via one ormore oxygen inlets in the battery chamber 600.

The electrolyte 601 may be an alkaline solution comprised of water as asolvent and one or more dissolved hydroxides, such as lithium hydroxide(LiOH), sodium hydroxide (NaOH), potassium hydroxide (KOH), or ammoniumhydroxide (NH₄OH). The electrolyte 601 may optionally contain additivesto promote or inhibit certain desired or undesirable reactions. Forexample, the electrolyte 601 may contain hydrogen evolution reactioninhibitor (e.g., Sn(OH)₆ ²⁻) and/or a Fe activator (such as a sulfidesalt such as bismuth sulfide (Bi₂S₃) or sodium sulfide (Na₂S)). In adischarging mode, the primary battery unit 110 may generate power and anoxygen reduction reaction (ORR) may occur on the cathode 603. In variousembodiments, the primary battery unit 110 is not configured to operatein a charging mode (or recharging mode).

As discussed above, in step 502 of method 500 the battery unit 110 maybe operated in a discharge mode to generate power output to the grid 102or any other system or device receiving power. In the discharge mode,the anode 602 may oxidize and oxidized anode material 604, such asoxidized anode particulate, oxidized anode powder, oxidized anodeshards, etc., may be generated in the battery chamber 600. Whileillustrated as having the oxidized anode material 604 falling throughthe electrolyte 601, the anode 602 may oxidize in place. The oxidizedanode material 604 may include Fe(OH)₂, Fe(OH)₃,Fe₂O₃, Fe₃O₄, FeOOH, orcombinations thereof when the electrolyte has a pH of greater than 6.

As discussed above, in step 504, the oxidized anode material 604 may becollected and removed from the battery chamber 600. Filters, pumps,valves, and access ports may be used in various embodiments to collectand remove the oxidized anode material 604. As discussed above, in step506, the oxidized anode material 604 may be reprocessed into chargedfuel (i.e., anode material 602). The metallurgical processing applied tothe oxidized anode material 604 may reconstitute the anode 602 which maybe replaced in the battery unit 110 in step 508 as discussed above.

While FIG. 6 is illustrated and discussed in relation to oxidized anodematerial 604, such as oxidized anode particulate, oxidized anode powder,oxidized anode shards, etc., being collected and removed, beingreprocessed into charged fuel, and being replaced in the battery unit110, the discussion of oxidized anode material 604 is merely forillustration purposes. Reduced cathode material may be substituted inthe various examples for the oxidized anode material 604 and reducedcathode material may be collected and removed, reprocessed into chargedfuel, and replaced in the battery unit 110 in a similar manner asdiscussed above.

FIG. 7 illustrates an embodiment configuration of refuelable batterythat may be used as a primary battery unit 110 in various embodiments.The refuelable battery illustrated in FIG. 7 may operate in a similarmanner to the refuelable battery discussed above with reference to FIG.6. The refuelable battery illustrated in FIG. 7 may be a Fe-air typebattery including a battery chamber 700 supporting an anode 701 ofpowdered Fe and a binder. Additionally, the anode 701 may include aconcentration of carbon (C), such as at a volume per volume percent(v/v%) concentration of 2 v/v%, which may be added before, during, orafter reduction of the anode 701 and which may aid in reduction andincrease conductivity of the anode 701. The anode 701 may be a packedbed of Fe powder and the binder. As an example, the anode 701 may havepreviously been reprocessed under hydrogen (H₂) at 800 degrees Celsiususing DRI processing. A porous separator 702 may support theelectrolyte, such as potassium and/or sodium hydroxide (e.g.,(K/Na(OH)). The outer wall of the battery chamber 700 may be formed of aporous gas diffusion electrode 703 that may operate as a cathode. Thegas diffusion electrode 703 may operate as an air inlet, such as anoxygen inlet, to provide air, such as air including oxygen, oxygen,etc., into the battery chamber 700. A carbon dioxide (CO₂) scrubber 704may be coupled to the air inlet, such as the oxygen inlet, to remove CO₂from air provided to the battery chamber 700. The CO₂ scrubber 704 maybe any type CO₂ scrubber, such as a selective membrane or other CO₂removing device. In certain other embodiments, the CO₂ scrubber 704 maybe a reactive pebble bed loaded with powdered NaOH which reacts with CO₂to form Na₂CO₃. The CO₂ scrubber 702 may be either regenerable or not.The anode 701 may be removable and replaceable to refuel the primarybattery unit 110. The refuelable battery illustrated in FIG. 7 may beexpected to achieve a 1.1 kWHr/kg Fe based on a geometry of 10 mA/cm²and expected polarization behaviors. Additionally, the porous gasdiffusion electrode 703 may be removable and replaceable to refuel theprimary battery unit 110.

FIG. 8 is a block diagram of another embodiment refuelable battery thatmay be used as a primary battery unit 110 in various embodiments. Therefuelable battery illustrated in FIG. 8 may operate in a similar mannerto the refuelable batteries discussed above with reference to FIGS. 6and 7. Refuelable battery illustrated in FIG. 8 may include arecirculation system 801 and a filter area 802 as part of the batterychamber 600. The recirculation system 801 may be configured to circulateelectrolyte 601 past the anode 602 and cathode 603 and through thefilter area 802. For example, the recirculation system 801 may include acirculation pump 806 configured to circulate electrolyte through thefilter area 802 and the rest of the battery chamber 600. As discussedabove, the anode 602 may be an iron or iron alloy anode. The anode 602may include iron, zinc, aluminum, and/or magnesium. The anode 602 may bea zinc (Zn), magnesium (Mg), or aluminum (Al), anode.

The anode 602 may include iron (Fe), zinc (Zn), magnesium (Mg), aluminum(Al), and/or an alloy formed substantially of one or more of iron, zinc,magnesium and/or aluminum. The anode 602 may include iron (Fe) or aniron alloy. The anode 602 may include zinc (Zn) or a zinc alloy. Theanode 602 may include magnesium (Mg) or a magnesium alloy. The anode 602may include aluminum (Al) or an aluminum alloy. As discussed above, theanode 602 may oxidize to form solid phase reaction products which may bedispersed or suspended in the electrolyte 601. The electrolyte 601passes through the recirculation system 801 to the filter area 802 andthe oxidized anode material 604 is filtered out of the electrolyte 601and trapped in the filter area 802. The filter area 802 may include afilter element, such as a foam, to act as a trap for the oxidized anodematerial 604. The foam may be seeded, such as with a metal hydroxide(e.g., calcium hydroxide (CaOH), etc.) to facilitate trapping of theoxidized anode material 604. The electrolyte 601 may have a high pHvalue, such as greater than 6. The filter area 802 may be a compartment,such as a bag, box, trap, or other type compartment that may befluidically separated from the battery chamber 600 by closing a valve805. The filter area 802 may then be drained of electrolyte 601. Theoxidized anode material 604 may be removed for reprocessing by openingaccess port 803 providing access to the filter area 802. Once theoxidized anode material 604 is removed, the access port 803 may beclosed, the valve 805 may be opened, and electrolyte 601 may once againbe filtered through the filter area 802 to trap oxidized anode material604. Another access port 807 may facilitate the insertion of a rechargedanode 602 into the battery chamber 600. The access port 807 may beconfigured to allow charged anode material (e.g., solid Fe) to be placedon an anode support 808 of the battery chamber 600 that suspends theanode 602 in the battery chamber 600. The refuelable battery illustratedin FIG. 8 may achieve a 1.3 kWhr/kg Fe for 3e⁻ discharge at 1.0V. Therefuelable battery illustrated in FIG. 8 may have a high impuritytolerance.

While FIG. 8 is illustrated and discussed in relation to oxidized anodematerial 604 being trapped in the filter area 802, being reprocessedinto charged fuel, and being replaced in the battery chamber 600, thediscussion of oxidized anode material 604 is merely for illustrationpurposes. Reduced cathode material may be substituted in the variousexamples for the oxidized anode material 604 and reduced cathodematerial may be trapped in the filter area 802, reprocessed into chargedfuel, and replaced in the battery chamber 600 in a similar manner asdiscussed above. For example, the access port 807 may be configured toallow charged cathode material to be placed on a cathode support 810 ofthe battery chamber 600 that suspends the cathode 603 in the batterychamber 600.

The foregoing method descriptions are provided merely as illustrativeexamples and are not intended to require or imply that the steps of thevarious embodiments must be performed in the order presented. As will beappreciated by one of skill in the art the order of steps in theforegoing embodiments may be performed in any order. Words such as“thereafter,” “then,” “next,” etc. are not necessarily intended to limitthe order of the steps; these words may be used to guide the readerthrough the description of the methods. Further, any reference to claimelements in the singular, for example, using the articles “a,” “an” or“the” is not to be construed as limiting the element to the singular.

Further, any step of any embodiment described herein can be used in anyother embodiment. The preceding description of the disclosed aspects isprovided to enable any person skilled in the art to make or use thepresent invention. Various modifications to these aspects will bereadily apparent to those skilled in the art, and the generic principlesdefined herein may be applied to other aspects without departing fromthe scope of the invention. Thus, the present invention is not intendedto be limited to the aspects shown herein but is to be accorded thewidest scope consistent with the principles and novel features disclosedherein.

What is claimed is:
 1. A refuelable battery, comprising: a batterychamber comprising: an electrode support configured to support anelectrode material within the battery chamber; a first access portconfigured to allow placement of the electrode material within thebattery chamber and on the electrode support; and a second access port,wherein the battery chamber is configured to trap expended electrodematerial generated from the electrode material while the refuelablebattery is operating in a discharge mode for removal of the expendedelectrode material from the battery chamber via the second access port.2. The refuelable battery of claim 1, wherein: the electrode support isan anode support; the electrode material is an anode material; and theexpended electrode material is oxidized anode material generated fromthe anode material while the refuelable battery is operating in thedischarge mode.
 3. The refuelable battery of claim 2, furthercomprising: an anode supported on the anode support; an air inlet in thebattery chamber configured to provide air into the battery chamber; andan electrolyte within the battery chamber in contact with the anode. 4.The refuelable battery of claim 3, wherein the anode material comprisesat least one of iron, zinc, aluminum, or magnesium.
 5. The refuelablebattery of claim 3, wherein the anode material comprises an iron alloy.6. The refuelable battery of claim 5, wherein the iron alloy comprisesiron and one or more of zinc, aluminum, magnesium, and carbon.
 7. Therefuelable battery of claim 3, wherein the anode material comprises azinc alloy, an aluminum alloy, or a magnesium alloy.
 8. The refuelablebattery of claim 3, wherein the battery chamber further comprises: afilter area configured to trap the oxidized anode material andaccessible by the second access port; and a circulation pump configuredto circulate the electrolyte through the filter area.
 9. The refuelablebattery of claim 8, wherein the filter area comprises a foam seeded withcalcium hydroxide.
 10. The refuelable battery of claim 8, wherein thefilter area is configured to be fluidically isolated from a portion ofthe battery chamber such that the electrolyte does not circulate into orout of the filter area from the portion of the battery chamber duringremoval of the oxidized anode material from the battery chamber via thesecond access port.
 11. The refuelable battery of claim 3, furthercomprising a carbon dioxide scrubber coupled to the air inlet.
 12. Therefuelable battery of claim 1, wherein: the electrode support is acathode support; the electrode material is a cathode material; and theexpended electrode material is reduced cathode material generated fromthe cathode material while the refuelable battery is operating in thedischarge mode.
 13. A method of operating a refuelable battery,comprising: discharging the battery to generate expended electrodematerial from an electrode; removing the expended electrode materialfrom the battery; and inserting another electrode into the battery. 14.The method of claim 13, wherein: discharging the battery to generate theexpended electrode material from the electrode comprises discharging thebattery to generate iron oxide or iron hydroxide oxidized anode materialfrom an iron or iron alloy anode; removing the expended electrodematerial from the battery comprises removing the oxidized anode materialfrom the battery; and inserting another electrode into the batterycomprises inserting another iron or iron alloy anode into the battery.15. The method of claim 14, further comprising: circulating anelectrolyte between a seeded trap area and the anode and cathodeelectrode area of the battery during operation; providing air into thebattery during the operation; draining the electrolyte from the seededtrap area before the step of removing; and removing the oxidized anodematerial from the seeded trap area after the step of draining.
 16. Themethod of claim 13, wherein: discharging the battery to generate theexpended electrode material from the electrode comprises discharging thebattery to generate an oxidized anode material; removing the expendedelectrode material from the battery comprises removing the oxidizedanode material from the battery; and inserting another electrode intothe battery comprises inserting another anode into the battery.
 17. Themethod of claim 16, further comprising: removing a reduced cathodematerial from the battery; and inserting another cathode into thebattery, wherein the another anode is formed from at least a portion ofthe removed oxidized anode material.
 18. The method of claim 13,wherein: discharging the battery to generate the expended electrodematerial from the electrode comprises discharging the battery togenerate a reduced cathode material; removing the expended electrodematerial from the battery comprises removing the reduced cathodematerial from the battery; and inserting another electrode into thebattery comprises inserting another cathode into the battery.
 19. Amethod for operating a refuelable battery system, comprising: providinga battery power plant comprising a set of refuelable batteries;operating the battery power plant for a time frame to supplement powerfrom a power source; and refueling the set of refuelable batteries. 20.The method of claim 19, wherein each of the refuelable batteriescomprises an anode comprising iron.
 21. The method of claim 20, wherein:the power source is a renewable power source; and the time frame is aweek or greater.
 22. The method of claim 20, wherein refueling the setof refuelable batteries comprises: removing one of more of the set ofrefuelable batteries from the battery power plant; transporting theremoved refuelable batteries to a reprocessing site; reprocessingmaterials within the removed refuelable batteries to refuel the removedrefuelable batteries; and transporting the refueled refuelable batteriesto the battery power plant and reinserting the refueled refuelablebatteries into the battery power plant.
 23. The method of claim 20,wherein power for the reprocessing is provided by the renewable powersource.
 24. The method of claim 19, wherein refueling the set ofrefuelable batteries comprises: removing materials from one or more ofthe set of refuelable batteries; reprocessing the removed materials at areprocessing site to generate charged fuel; and inserting the chargedfuel into one or more of the set of refuelable batteries from which theremoved materials were removed.
 25. The method of claim 24, wherein theremoved materials are oxidized anode materials and charged fuelcomprises a reduced anode.
 26. The method of claim 25, wherein thereprocessing comprises reduction, smelting, or electrolysis.
 27. Themethod of claim 25, wherein the reprocessing comprises reduction of theoxidized anode materials using a natural gas or coal burning furnace.28. The method of claim 25, wherein the reprocessing comprises usingcarbon included in the oxidized anode materials to enhance the reductionof the oxidized anode materials.
 29. The method of claim 25, whereinpower for the reprocessing is provided by the renewable power source.30. The method of claim 24, wherein the removed materials are cathodematerials.